Variable delivery pump

ABSTRACT

A pump utilizing basically the same pumping elements as currently in use in a slipper-type pump having a rotor rotatable in a cam ring providing a double-lobed working chamber and wherein the rotor carries a plurality of slipper-type pumping elements which are free to move radially and to rock angularly in following the adjoining wall of the bore contour is modified by providing the cam ring and the adjoining pressure plate with two sets of multiple passages, for example, sets of six, and adding a freely rotatable actuator plate movable from a neutral position to either a forward position or a reverse position, thereby to preferentially bias the actuator plate in such a manner as to selectively exclude or include egress holes.

United States Patent 91 Drutchas et al.

[ 1 VARIABLE DELIVERY PUMP [75] Inventors: Gilbert H. Drutchas; Hubert M. Clark, both of Birmingham; Harold A. Melendy, Troy, all of Mich.

[73] Assignee: TRW Inc., Cleveland, Ohio [22] Filed: Nov. 24, 1971 [21] Appl. No.: 201,876

UNITED STATES PATENTS 2,570,411 Vickers ..4l8/l59 Mueller ..4l8/159 FOREIGN PATENTS OR APPLICATIONS 216,191 2/1958 Australia 418/159 [451 May 1, 1973 Primary Examiner-Carlton R. Croyle Assistant Examiner-Richard E. Gluck Attorney-Carlton Hill et a1.

[57] ABSTRACT A pump utilizing basically the same pumping elements as currently in use in a slipper-type pump having a rotor rotatable in a cam ring providing a double-lobed working chamber and wherein the rotor carries a plurality of slipper-type pumping elements which are free to move radially and to rock angularly in following the adjoining wall of the bore contour is modified by providing the cam ring and the: adjoining pressure plate with two 'sets of multiple passages, for example, sets of six, and adding a freely rotatable actuator plate movable from a neutral. position to either a forward position, or a reverse position, thereby to preferentially bias the actuator plate in such a manner as to selectively exclude or include egress holes.

12 Claims, 10 Drawing Figures Patented May 1, 1973 3,730,653

4 Sheets-Sheet 2 FORM/12D INVENTORS G/L 5627 /4 02070445 da s. ATTORNEYS MARQD flMa/v r v Patented May 1, 1973 3,730,653

4 Sheets-Sheet 4 FOR WA RD INVENTORS Gm 55; Dev/471045 uaasr M [445% A AkmD K). Mfa away By M MW a W ATTORNEYS VARIABLE DELIVERY PUMP BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to positive displacement pumps and more particularly relates to a pump of the type using slipper-type pumping elements wherein a plurality of slipper-type pumping elements are carried in a rotor and are free to move radially and to rock angularly in following the adjoining bore wall of a pumping chamber.

2. Prior Art Variable displacement pumps in use today are generally complex devices typified by some of the com mercially available structures. For example, in one form of axial piston-type variable displacement pump, the displacement is controlled by the inclination of the non-rotating hanger, usually called a swash plate". That inclination, in turn, controls the stroke of several axial pistons grouped around the drive shaft in a cylinder block which rotates with the shaft. Such design requires a port plate which rotates with the cylinder block to properly time the connection of the piston cylinder cavities to the appropriate housing outlet and/or inlet ports.

In a second example of an axial piston-type variable displacement pump, the displacement is controlled by the axial position of the piston sleeves which adjust the amount of oil that is permitted to flow back into the inlet in the course of a piston stroke. Thus, zero backflow gives maximum displacement and 100 percent back-flow gives a zero displacement. The swash plate rotates and the inclination of its face is fixed, and thus, the piston stroke is fixed.

In a third example of an axial piston-type variable displacement pump there is utilized a split flow system in which the displacement of from two to eight pistons can be discharged into the line circuit and the displacement of the piston not on line can either be directed back to the sump or into other circuits. The wobble plate or so-called swash plate, rotates and the inclination of its face is fixed. Thus, the piston stroke is fixed and the discharge of such pump from a minimum to a maximum flow is stepped at selected fixed values.

In a fourth variable displacement pump, radial pistons are provided with means for varying the piston stroke and hence the displacement. In this form of pump, the eccentricity of the cam on the shaft is varied and the piston stroke is changed by the pressure in the crank case.

In a fifth example of a variable displacement pump, a vane-type pump is provided in which the displacement is controlled by the eccentricity of the pump pressure ring in relation to the rotor. The greater the eccentricity, the greater the displacement of the pump.

SUMMARY OF THE INVENTION In accordance with the principles of the present invention, a positive displacement pump having slippertype pumping elements is equipped with a freely rotatable actuator plate. The actuator plate cooperates with a ported pressure plate and a cam ring, each provided with a series of discharge passages spaced circumferentially. Thus, flow is swept into the working are within the cam ring and pump output seeks to egress through the multiple outlet passages. The actuator plate is freely rotatable by a motion clockwise or counterclockwise and places the outlet port kidneys in a preferentially biased position to allow an escapement of fluid from any consecutive combination of holes in the set of discharge passages while allowing the holes not in register with the outlet kidneys to pass into inlet by-pass openings into a zone at reduced pressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view ofa pump incorporating the principles of the present invention;

FIG. 2 is a cross-sectional view taken substantially on the plane ofline II-II of FIG. 1;

FIG. 3 is a cross-sectional view taken on the plane of line IIIIII of FIG. I;

FIG. 4 is a cross-sectional view taken on the plane of line IV-IV of FIG. 1;

'FIG. 5 is a cross-sectional view with parts removed showing the actuator plate of the present invention in greater detail;

FIG. 6 is a further view of the actuator plate taken on line VI-VI of FIG. 5;

FIG. 7 is a further view of the actuator plate taken on the plane of line VII-VII of FIG. 5;

FIG. 8 is a cross-sectional view taken on line VIII- VIII of FIG. 1;

FIG. 9 is a cross-sectional view taken on line IX--IX of FIG. I and FIG. 10 is a crosssectional view taken on line X--X of FIG. I.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS The variable delivery pump-of the present invention is shown generally at 15 and comprises a casing 16 open atone end as at 17 to provide a cavity terminating in a bottom wall forming an end wall 18. The open end 17 is closed by a cover 19 locked in assembly with the casing 16 by means of a ring 20 seated in a recess 21 inwardly of the open end 17. The cover 19 is sealed by means of an O ring sealing member 22. A coil spring 23 constitutes a continuous biasing means andis bottomed against the cover 19 as well as against a pressure plate 24 sealed in the casing 16 by means of a sealing member 26. The pressure plate 24 has one or more axially extending openings 27 formed therein. In this embodiment two openings 27 are provided and each is counterbored as at 28, thereby to receive a ball-type relief valve 29 which seats on the edges of the opening 27 and is spring-biased by a coil spring 30 bottomed against a closure cap 31. The closure caps 25 each have a centrally disposed opening 27a, thereby to facilitate pressurization of a pressure chamber 25 disposed between the cover 19 and the pressure plate 24 for axial loading of the pump assembly.

The end wall 18 is intersected by a passage 35 through which extends a shaft 32 journaled in a pair of axially spaced bearing sleeves 33 and 34. A shaft seal is shown generally at 36 between the casing 16 and the shaft 32.

Near the inner end of the shaft 32 is a coupling spline 37 in rotatable driving engagement with a rotor 38. As shown in FIG. 3, the rotor 38 has a plurality of notches 39 formed in its periphery and each notch receives a slipper-type pumping element shown generally at 40 which is free to move radially and to rock angularly in following the adjoining bore wall 41 of a cam ring 42. In this particular exemplary structure, the cam ring 42 has a bore wall 41 prescribing a so-called double-lobe contour so that there are two crescent-shaped working chambers 43 and 44, each having a corresponding inlet zone and outlet zone and so that two separate pumping impulses are generated on each rotation of the rotor 38. It will be understood that the usual springs 46 may be provided if desired to provide an initial biasing force moving the slipper-type pumping elements radially outwardly.

A front port plate is shown generally at 47 adjacent to the cam ring 42. In accordance with the principles of the present invention, a stator ring 48 is interposed between the front port plate 47 and the end wall 18 of the casing 16. A pair of dowel pins, each indicated at 49, passes through the stator ring 48 and the respective opposite ends extend into corresponding recesses formed in the front port plate 47 and the casing 16. In accordance with the principles of the present invention, an actuator plate is shown generally at 50 and is freely rotatable within the confines prescribed by the front port plate 47 and the end face 18, the actuator plate 50 being, in effect, joumaled on the stator 48 which in turn has one of the bearing rings 33 radially inwardly thereof for providing a bearing surface to the shaft 32.

The actuator plate 50 has an upwardly extending boss 51 in which is formed a shifter slot 52 receiving a finger portion 53 of a shifter arm 54 carried on a shaft 56 which in turn is rotatably supported in a bearing sleeve 57 carried by an upwardly projecting bearing boss 58 formed in the casing 16. The shaft 56 projects outwardly of the casing and has a portion 59 projecting into an accessible position for attachment to an operating mechanism. A shaft seal is shown generally at 60. As shown in FIG. in conjunction with FIG. 1, the casing 16 has 'a pair of porting bosses 61 and 62 in which is formed a pair of housing ports 63 and 64, respectively. A bleeder passage 66 extends through the casing, thereby to communicate the interior of the pump with the shaft seal 36.

Referring to FIG. 10, the housing 16 is formed with a bore 633 and a bore 64a each constituting an extension of a corresponding bore 63 and 64, respectively. The housing 16 also has axially extending passages intersecting such bores 63a and 640 which are shown at 63b and 64b, respectively. It will be appreciated that the arcuate kidney-shaped passages 63b and 64b intersect the wall 18 in registering adjacency with the actuator plate 50.

Referring now to FIGS. 1 and 3, the cam ring 42 is retained in non-rotatable relationship relative to the end plate member 24 and the porting plate 47 by a pair of dowel pins 67.

The present invention shows a cam ring with a double-lobed pumping bore 41, thereby providing two crescent-shaped working chambers 43 and 44. It is contemplated by the present invention that the cam ring 42 is particularly characterized by a'plurality of circumferentially spaced apart multiple egress passages 70, 71, 72, 73, 74 and 75. On the opposite diametral side of the cam ring 42 is formed a corresponding plurality of egress passages 80, 81, 82, 83, 84 and 85. Each of the passages -75 and -85 has an axially extending portion and portions are formed at opposite axial ends which extend radially inwardly to intersect the bore wall 41 as shown at 76. p

The cam ring 42 is also notched as at 77 and at 87, thereby to provide an inlet zone for each corresponding working arc 44 and 43.

Referring now to FIG. 4, the porting plate 47 has a corresponding series of egress ports formed on opposite diametral sides thereof indicated at 90, 91, 92, 93, 94 and 95 on one side and at 100, 101, 102, 103, 104 and 105 on the opposite side.

It is contemplated by the present invention that the housing means provides a constraint at each end of the stack of pump parts and the stationary ring 48 constitutes a fixed stator held in stationary rotary position in a fixed and anchored relation relative to the porting plate 47 and the housing 16.

In accordance with the present invention, the actuator plate 50 is freely rotatable by a motion clockwise or counterclockwise from a neutral position to either a forward position or a reverse position, as shown by legends in FIGS. 2 and 8.

The structural configuration of the actuator plate 50 can be seen in FIG. 1 when considered in conjunction with FIGS. 5, 6, 7 and 8. Thus, the actuator plate 50 is a generally ring-shaped plate member having an inner circular wall and an outer generally circular periphery 111. Near the top thereof, i.e., the top when using the orientation of FIGS. 5 and 8, the outer periphery 111 is broken by a radially outwardly projecting boss 51 in which is formed the shifter slot 52 for receiving the finger 53 of the shifter arm 54.

The outer wall or periphery 111 has a lower radial notch 112 formed therein as well as an upper radial notch 113. The actuator plate 50 is further characterized by having a first radial face 114 which slidably engages the adjoining face of the porting plate 47 and an opposite radial face 116 which slidably engages the adjoining wall 18 of the housing 16. The notch 113 extends into the face 114 but does not extend axially through the thickness of the actuator plate 50.

The notch 112, on the other hand, extends axially through the actuator plate 50 from the radial wall 114 until it opens into a larger radial notch 117 formed in the wall 116.

Referring specifically to FIG. 5, it will be noted that the wall 114 has formed therein a pair of arcuate kidney-shaped recesses 118 and 119, respectively.

Referring to FIG. 8, the face or radial wall 116 has a kidney-shaped recess 120 formed therein. At opposite ends of the kidney-shaped recess 120, there is formed a somewhat elongated port 121 which is a through port and at the opposite end a correspondingly elongated through port 122.

Referring to FIG. 9, the wall 18 of the housing 16 is shown in which is formed the port passages 63b and 64b. For purposes of orientation, there is superimposed on FIG. 9 in dotted lines the actuator plate outlet port 120 and the actuator plate inlet port 1 17.

It will be appreciated that the housing 16 forms a plenum P around the pump components including the cam ring 42, the porting plate 47 and the actuator plate 50.

In operation, fluid from the plenum is drawn into the pump through the cam inlet passages 77 and 87 and the fluid is swept into the respective working arcs 44 and 43. Transfer fluid enters the arcuate converging bore 41 and since the bore alternately diverges and then converges, as the slipper-type pumping elements traverse the working arcs 43 and 44, pump output seeks to egress through the passages 70-75 and 80-85. The actuator plate 50 is freely rotatable by a motion clockwise or counterclockwise and places the outlet port kidneys 118 and 119 in a preferentially biased position to allow an escapement of fluid from any consecutive combination of holes 70-75 and 80-85, while allowing the holes not in register with the outlet kidneys 118 and 119 to pass into the inlet by-pass notches 112 and 113 and into the plenum P. Fluid collected under pump-generated pressure in the outlet kidneys 118 and 119 is directed through the outlet ports 121 and 122 and through the outlet kidney 120 into a corresponding one of the passages for discharge to a point of utilization through either the port 63 or 64.

Because of the constructional features of the present invention, there are essentially three different modes, i.e., a neutral position of the actuator plate 50, a forward position and a reverse position.

Neutral Position the inlet notches 112 and 113. The result is a net zero output. While the inlet notches 112 and 113 do not cover all of the individual ports, for example, the port 90 and the port 95 and the port 100 and the port 105 in register respectively with the passages 70-75, 8085, it

should be understood that such ports do not provide a net output since some of the egress passages are open to outlet to sustain system leakage.

Forward Position Assuming the actuator plate moved to the forward position, flow output egressing from the egress openings -75 and -85 enters the ports -95 and -105 and the outlet kidneys 118 and 119, which are preferentially biased to exclude or include egress ports depending on how far in a counterclockwise direction in terms of degrees that the actuator plate 50 is biased. The outlet flow entering the kidney ports 118 and 119 passes through the outlet ports 121 and 122 and thence through the outlet kidney into a corresponding passage 63b, 63a to the outlet port 63. Return flow passes through the port 64, the passage 64a, 64b and through the inlet port 112 to plenum P.

Reverse Position 1n the reverse position, flow output egressing from the passages 70-75 and 80-85 and the respective ports 90-95 and 100-105 are once again directed through the outlet kidneys 118 and 119 which are preferentially biased to exclude or include egress ports, depending on how far in a clockwise direction in terms of degrees the actuator plate 50 is biased. Again, the outlet flow passes through the ports 121 and 122, through the outlet kidney 120 and through the passage 64b, the passage 64a and the outlet port 64. In this position of operation, return flow passes through the port 63, the passages 63:: and 63b, through the inlet 112 and into the plenum P.

One of the relief valves has its opening 27 over the passage 75 in the cam ring 42 while the other has its opening over the cam passage 80. When the actuator plate 50 is in the forward position, the by-pass notch 113 connects the cam passage 75 to the plenum, and the pressure chamber 25 receives its pressure through the check valve over the cam passage 80 which remains connected to the actuator passage 118 and thence to the pump outlet. When the actuator plate 50 is in the reverse position, its by-pass notch 112 connects the cam passage 80 to the plenum, the check valve over it closes and the pressure chamber 25 receives its pressure through the check valve over the cam passage 75 which remains connected to the actuator plate passage 118 and thence to the pump outlet.

The advantages of the present invention reside in the ability to obtain a variable discharge pump capable of high pressure and high speed at a reasonable cost. Unlike the complicated inclinable hanger, shoe retainer and other elements in a swash plate type pump, such complicated parts are replaced in the present invention by the actuator plate 50. The torque forces needed to rotatably adjust the actuator plate 50 are very small and flow from the pump can be reversed according to the present invention without additional valving.

While the actuator plate 50 is shown adjusted by a "finger or slot means or by an angular shiftable arm, it will be understood the angular adjustment of the plate could be adjusted by gearing, either worm or spur, or by other mechanical means.

Although minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art. a

We claim as our invention:

1. In a pump of the type wherein a rotor carries a plurality of slipper-type pumping elements which are free to rock angularly and to move radially in following the adjoining wall of a pumping chamber, the improvement of:

a freely rotatable actuator plate movable from a relative neutral position to either a forward position or to a reverse position, clockwise and counterclockwise, respectively, and means forming adjacent to the pumping chamber and circum-jacent the pumping chamber a set of multiple egress passages spaced circumferentially apart from one another for selective register with said actuator plate, said actuator plate having outlet and inlet by-pass recesses disposed to selectively exclude or inelude egress passages for varying the delivery of the pump. 2. In a pump as defined in claim 1 and further characterized by said means forming said egress passages, comprising a cam ring in which the rotor ly engageable with said actuator plate.

4. In a pump as defined in claim 3 and adjustment means for adjustably moving said actuator plate angularly.

5. In a pump as defined in claim 4, wherein said adjustment means includes:

finger and slot means for angularly shifting said actuator plate towards either forward or reverse positions. 6. A pump comprising housing means forming a cavity and having bearing means therein for journaling a shaft, a shaft journalled in said bearing means and having a rotor rotatable within said cavity, a cam ring in said cavity having a pumping bore formed therein and in which said rotor rotates, said rotor having a plurality of slipper-type pumping elements carried thereby free to rock angularly and to move radially in following the adjoining bore wall of a pumping chamber,

said cam ring being peripherally notched to form an inlet zone and having a plurality of circumferentially spaced apart egress openings to form an outlet zone,

a port plate adjacent to said cam ring and having a corresponding plurality of circumferentially spaced apart axially extending egress ports formed therein registering with said egress openings in said cam ring,

and an actuator plate supported and confined for rotational movement between said housing means and said port plate and rotatable from a vertical position to either a forward or a reverse position, said actuator plate having ports formed therein disposed to selectively exclude or include egress ports in said porting plate,

thereby to selectively vary the delivery of the pump. 7. A pump as defined in claim 6 and further characterized by an adjustment means for moving said actuator plate selectively in either direction.

8. A pump as defined in claim 7 and further characterized by said actuator plate having radially outwardly projecting boss means formed with a shifter slot therein, and said adjustment means comprising an angularly shiftable arm having a finger received in said shifter slot to move said actuator plate selectively in either angular direction. 9. In a pump, a cam ring having a double lobed pumping chamber bore, a rotor having pumping elements rotatable in said bore, each lobe of said bore com rising a working are forming arcuate diverging an converging bore sections,

said cam ring having a plurality of circumferentially spaced apart egress openings formed therein,

whereby as the pumping elements traverse each working arc pump output seeks to egress through said openings,

and an actuator plate mounted to be freely rotatable by a motion clockwise or counterclockwise from a neutral position and having outlet kidney ports and inlet by-pass ports formed therein selectively placed in a preferentially biased position to allow escapement of pumped fluid from any consecutive combination of egress openings while allowing egress openings not in register with outlet kidney ports to by-pass into inlet by-pass kidneys.

' 10. In a pump as defined in claim 9,

a porting plate interposed between said cam ring and said actuator plate having a corresponding number of egress ports extending axially therethrough and operating to improve the porting control between said cam ring and actuator plate.

1 1. In a pump as defined in claim 9,

housing means enclosing said cam ring and having inlet and outlet passage means formed therein through which inlet and outlet fluid is directed to and from the pumping chamber.

12. In a pump as defined in claim 9 and adjustment means for selectively angularly positioning said actuator plate. 

1. In a pump of the type wherein a rotor carries a plurality of slipper-type pumping elements which are free to rock angularly and to move radially in following the adjoining wall of a pumping chamber, the improvement of: a freely rotatable actuator plate movable from a relative neutral position to either a forward position or to a reverse position, clocKwise and counterclockwise, respectively, and means forming adjacent to the pumping chamber and circumjacent the pumping chamber a set of multiple egress passages spaced circumferentially apart from one another for selective register with said actuator plate, said actuator plate having outlet and inlet by-pass recesses disposed to selectively exclude or include egress passages for varying the delivery of the pump.
 2. In a pump as defined in claim 1 and further characterized by said means forming said egress passages, comprising a cam ring in which the rotor rotates and in which cam ring is formed a bore wall providing a pumping chamber for the pumping elements, said cam ring having formed therein a plurality of circumferentially spaced multiple egress passages forming said passages circumjacent the pumping chamber.
 3. In a pump of the type as defined in claim 2 wherein said means defining said egress passages additionally comprises a porting plate having a corresponding plurality of axially extending circumferentially spaced apart multiple egress passages forming said passages adjacent the pumping chamber and being cooperatively engageable with said actuator plate.
 4. In a pump as defined in claim 3 and adjustment means for adjustably moving said actuator plate angularly.
 5. In a pump as defined in claim 4, wherein said adjustment means includes: finger and slot means for angularly shifting said actuator plate towards either forward or reverse positions.
 6. A pump comprising housing means forming a cavity and having bearing means therein for journaling a shaft, a shaft journalled in said bearing means and having a rotor rotatable within said cavity, a cam ring in said cavity having a pumping bore formed therein and in which said rotor rotates, said rotor having a plurality of slipper-type pumping elements carried thereby free to rock angularly and to move radially in following the adjoining bore wall of a pumping chamber, said cam ring being peripherally notched to form an inlet zone and having a plurality of circumferentially spaced apart egress openings to form an outlet zone, a port plate adjacent to said cam ring and having a corresponding plurality of circumferentially spaced apart axially extending egress ports formed therein registering with said egress openings in said cam ring, and an actuator plate supported and confined for rotational movement between said housing means and said port plate and rotatable from a vertical position to either a forward or a reverse position, said actuator plate having ports formed therein disposed to selectively exclude or include egress ports in said porting plate, thereby to selectively vary the delivery of the pump.
 7. A pump as defined in claim 6 and further characterized by an adjustment means for moving said actuator plate selectively in either direction.
 8. A pump as defined in claim 7 and further characterized by said actuator plate having radially outwardly projecting boss means formed with a shifter slot therein, and said adjustment means comprising an angularly shiftable arm having a finger received in said shifter slot to move said actuator plate selectively in either angular direction.
 9. In a pump, a cam ring having a double lobed pumping chamber bore, a rotor having pumping elements rotatable in said bore, each lobe of said bore comprising a working arc forming arcuate diverging and converging bore sections, said cam ring having a plurality of circumferentially spaced apart egress openings formed therein, whereby as the pumping elements traverse each working arc pump output seeks to egress through said openings, and an actuator plate mounted to be freely rotatable by a motion clockwise or counterclockwise from a neutral position and having outlet kidney ports and inlet by-pass ports formed therein selectively placed in a preferentially biased position to allow escapement of pumped fluid from any consecutive coMbination of egress openings while allowing egress openings not in register with outlet kidney ports to by-pass into inlet by-pass kidneys.
 10. In a pump as defined in claim 9, a porting plate interposed between said cam ring and said actuator plate having a corresponding number of egress ports extending axially therethrough and operating to improve the porting control between said cam ring and actuator plate.
 11. In a pump as defined in claim 9, housing means enclosing said cam ring and having inlet and outlet passage means formed therein through which inlet and outlet fluid is directed to and from the pumping chamber.
 12. In a pump as defined in claim 9 and adjustment means for selectively angularly positioning said actuator plate. 